1. Field of the Invention
The present invention relates to direct current (DC) powered electrodialysis reversal systems, and in particular, to a solar-powered DC system with low power requirements and the ability to operate unattended for extended periods.
2. Prior Art
A water treatment system that uses solar-powered electrodialysis reversal was previously developed by the United States Bureau of Reclamation. This system used alternating current (AC) power for reversing controls. This system has proved to be too power intensive due to the losses that occur in converting DC power from the solar-power modules into AC power to run the controls. A discussion of this system is provided in Eisenhauer, R. J., and L. A. Haugseth, "Solar Photovoltaic Electrodialysis Demineralization of Brackish Water," U.S. Department of the Interior, Bureau of Reclamation, Interim Report, October 1983.
Another solar-powered electrodialysis system is disclosed in Lundstrom, J. E., "Water Desalting by Solar Powered Electrodialysis," Desalination, 1979. However, because this system is non-reversing, the membranes stack fouls and the system must be cleaned with chemicals on a regular basis. Consequently, the operating and maintenance requirements are high, and the system is not capable of running unattended for long periods of time.
Accordingly, the need exists for a water desalting system that overcomes the disadvantages of the prior art systems mentioned above.